How Tropical Storm Arthur Will Affect Your 4th of July Plans

— -- Tropical Storm Arthur is expected to batter the East Coast just in time for Fourth of July fireworks.

The storm's maximum sustained winds strengthened overnight to 60 mph. Arthur is moving up the Atlantic Ocean near the coast of Florida today, and will likely become a hurricane by Thursday, the National Hurricane Center said.

North and South Carolina are expected to get hit the hardest.

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"I really think the Outer Banks get that first hurricane of our Atlantic season," ABC News senior meteorologist Ginger Zee said.

A stretch of North Carolina coastline from Bogue Inlet up to Oregon Inlet is under a hurricane watch. A tropical storm watch is in effect for parts of Florida and South Carolina.

The northeast will see rain, but probably not a hurricane, Zee said.

"I think you'll have rough surf going into the weekend, but I do not think this is going to be by any means a direct hit," she said.

In New York, there's a 60 percent chance of rain on Friday, but the skies are clear and the sun is out for the rest of the holiday weekend.

There could also be some minor flooding in the northeast.

The forecast is already putting a damper on holiday plans.

Lifeguards in Florida raised red flags to warn of rough surf and rip currents, and swimmers at some beaches were advised to only go in the areas of water where lifeguards are stationed.

On North Carolina's Outer Banks, officials are closing the Cape Lookout National Seashore at 5 p.m. today. It will reopen when it's safe.